Links between bismuth incorporation and surface reconstruction during GaAsBi growth probed by in situ measurements
Links between bismuth incorporation and surface reconstruction during GaAsBi growth probed by in situ measurements
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DOI：
10.1063/1.5111932
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发表时间：
2019-09-07
影响因子：
3.2
通讯作者：
Fontaine, C.
中科院分区：
文献类型：
--
作者：
Cornille, C.;Arnoult, A.;Fontaine, C.
采用原位曲率监测和反射式高能电子衍射方法，研究了GaAsBi分子束外延生长过程中Bi的掺入和表面重构。生长温度和流量比已经连续变化。As/Ga原子比接近统一已被应用于生长温度效应的研究。在（1x 3）重建下的生长制度，Bi掺入被发现是独立的生长温度，Bi解吸是微不足道的温度。相反，一旦达到（2x 1）重构状态，Bi掺入就变得高度依赖于生长温度。仅对于最低温度，Bi掺入在（2x 1）重构期间达到与（1x 3）重构相同的水平。当As/Ga通量比增加时，观察到在（2x 1）重构区域中GaAsBi生长的铋掺入减少。我们的研究结果表明，（1x 3）和（2x 1）的表面重建总是连续观察到的能量障碍，必须克服过渡从（1x 3）到（2x 1）重建，与此机制是温度依赖性。最后，已经确定了重建的表面应力的差异。
Bismuth incorporation and surface reconstruction have been studied simultaneously during GaAsBi growth by molecular beam epitaxy by means of in situ wafer curvature monitoring and reflection high energy electron diffraction, respectively. Growth temperature and flux ratio have been varied successively. As/Ga atomic ratio close to unity has been applied for the study of the growth temperature effect. During the growth regime under the (1x3) reconstruction, Bi incorporation is found to be independent of the growth temperature, for temperatures where Bi desorption is insignificant. On the contrary, Bi incorporation becomes highly dependent on the growth temperature as soon as the (2x1) reconstruction regime is reached. Only for the lowest temperatures, the Bi incorporation reaches the same level during the (2x1) reconstruction than for the (1x3) reconstruction. When the As/Ga flux ratio is increased, the bismuth incorporation is observed to decrease for GaAsBi growth in the (2x1) reconstruction regime. Our results indicate that the (1x3) and (2x1) surface reconstructions are always successively observed and that an energy barrier has to overcome to transit from the (1x3) to the (2x1) reconstruction, with this mechanism being temperature dependent. Finally, a difference in surface stress with reconstruction has been identified.